Heating devices for engines for different types of vehicles or vessels are well known. The purpose of these is to preheat the engine by a direct or indirect heating of the engine oil or coolant, such that it easily starts in cold weather, and will reduce the fuel consumption/exhaust related to cold-starting the engine. Corresponding heating devices for other mechanical units in a vehicle or vessel, such as gearbox, hydraulics system, transmission system, are also known. For the sake of simplicity, the term “engine heater” will mainly be used in the following, even though these can also be used for heating other components.
There are different types of engine heaters, inter alia those that heat the engine coolant. A variant of such engine heaters comprises a container having a heating element. The container has an inlet opening and an outlet opening such that the engine coolant hose can be cut and the hose ends coupled to these openings. The engine heater is thereby a part of the engine cooling circuit, and the coolant flowing through the beholder is heated by the heating element and circulated in the engine's cooling circuit. An engine heater of this type is often referred to as a “hose heater”.
EP 2 462 339 A1 describes electrical heating device for heating a liquid in a vehicle, comprising a container and a heating plate, where the fluid in the container flows past the heating plate and where the heating plate is connected to an energy source via electrical wires. The heating plate contains a number of PTC elements (“Positive Temperature Coefficient”) and the container is produced from a thermoplastic material.
U.S. Pat. No. 5,408,960 describes a heating device with a container with an electrical, thermostat-controlled, heating element and a pump which drives the coolant in the cooling circuit. The container has connection stubs for coolant inlet and outlet.
EP 1 375 997 B1 describes a heating device for a fluid pipe, particularly for heating gases ventilated from a crankcase in a combustion engine, with a heating element and a holder for the heating element. The holder has a protrusion which is arranged for receiving the heating element and is shaped to be pushed into a shaft in the fluid pipe. The shaft has a wall which borders on the inside of the fluid pipe. It is also described that the heating element affects the outer wall of the fluid pipe.
There is a need for a heating device which is more compact, easier to produce and assemble, and also is more efficient than the known heating devices.